PARIS, Jan 21 (Reuters) - The board of French gas and power group Engie has decided to keep the roles of chief executive and board chair separate, French Finance Minister Bruno Le Maire said on Sunday.

The decision means that the company will appoint a new board chairperson after current chairman Gerard Mestrallet retires in May and Chief Executive Isabelle Kocher will not combine both roles.

“There is no question of a chaperone. She has done a very good job running Engie... but it turns out that the board of Engie has decided to dissociate the functions of CEO and chair of the board, we must respect this choice of governance,” Le Maire said on BFM TV.

In many French-listed companies the CEO also chairs the board, and French media have reported that Kocher - who is the only female CEO among the Paris bluechip CAC40 index companies - had made a bid to combine both roles.

The French state, which has a 24.1 percent stake in Engie, has five representatives on Engie’s 19-member board.

Kocher, who was appointed CEO in May 2016 after Mestrallet gave up that role, said on Sunday she would welcome a new chair if the right person could be found after Mestrallet retires.

“If a new chair were to join us and he is compatible, believes in our strategy and helps us to accelerate it, I would be delighted,” Kocher said on France’s CNEWS television.

Kocher denied media speculation about disagreements between her and Mestrallet. “He made this company into what it is and I thank him for all he has done to put us in a situation to succeed,” she said.

Since taking the CEO role, Kocher has focused Engie’s strategy on renewables, grids and energy services and has sold nearly 15 billion euros ($18 billion) worth of fossil-fuel related activities. ($1 = 0.8183 euros) (Reporting by Geert De Clercq and Myriam Rivet; Editing by John Stonestreet and Susan Fenton)